1. Field
The present disclosure relates to a display device including a liquid crystal display (LCD), a viewing angle control method for the liquid crystal display, computer program storage device with a viewing angle control program, and a mobile terminal.
2. Description of the Related Art
In general, one available method for preventing others from peeping or viewing information or the like displayed on a screen of a liquid crystal display of, for example, a mobile phone terminal is to control the viewing angle of the liquid crystal display.
Three types of methods for controlling the viewing angle of a liquid crystal display are available including first to third viewing angle control methods as follows:
The first viewing angle control method is a method in which, as disclosed in http://www.sharp.co.jp/products/device/about/lcd/veil/index. html, searched Jul. 1, 2010, a liquid crystal display for viewing-angle control is placed on the top of a liquid crystal display for image display and the viewing angle is controlled using the liquid crystal display for viewing-angle control.
The second viewing angle control method is a method in which, as disclosed in http://www.n-keitai.com/n703id/fc.html, searched Jul. 1, 2010, the contrast value of an image displayed on a liquid crystal display is reduced.
The third viewing angle control method is a method in which, as disclosed in http://www.sharp.co.jp/products/sb831sh/text/veilview.html, searched Jul. 1, 2010, data of an image displayed on a liquid crystal display is provided in the form of mixture of front-view image data and oblique-view image data.
Other viewing angle control methods of the related art include techniques disclosed in Japanese Unexamined Patent Application Publications No. 2007-17988 (FIG. 1) and No. 2009-64025 (FIG. 1).
Japanese Unexamined Patent Application Publication No. 2007-17988 discloses a viewing angle control method in which a liquid crystal display panel on which an image is displayed by spatial light modulation, and a circuit that switches liquid crystal of the panel between a first configuration in a first mode in which an image displayed using the liquid crystal display panel is visible from a wide range of viewing angles and a second configuration in a second mode in which an image displayed using the liquid crystal display panel is visible only from a narrow range of viewing angles are provided to facilitate in-plane switching between a public viewing mode and a private viewing mode.
Japanese Unexamined Patent Application Publication No. 2009-64025 discloses a viewing angle control method in which a display device includes, as a display panel, a liquid crystal display panel on which an image is displayed by spatial light modulation, and a circuit that switches, using liquid crystal of the panel, between a first configuration in a first mode in which an image displayed using the liquid crystal display panel is visible from a wide range of viewing angles and a second configuration in a second mode in which an image displayed using the liquid crystal display panel is visible only from a narrow range of viewing angles, and achieves in-plane switching between a public viewing mode and a private viewing mode.